{"id":283331,"date":"2023-10-14T21:35:46","date_gmt":"2023-10-14T19:35:46","guid":{"rendered":"https:\/\/climatescience.press\/?p=283331"},"modified":"2023-10-14T21:35:50","modified_gmt":"2023-10-14T19:35:50","slug":"blinded-by-antarctica-reports-2023","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=283331","title":{"rendered":"Blinded by Antarctica Reports\u00a02023"},"content":{"rendered":"\n
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Even if Antarctica lost 200 Gt\/yr. for the next 1000 years, it would only approach 1% of the ice sheet.<\/mark><\/em><\/strong><\/p>\n\n\n\n

From Science Matters<\/a><\/p>\n\n\n\n

By\u00a0Ron Clutz<\/a><\/p>\n\n\n\n

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Special snow goggles for protection in polar landscapes.<\/figcaption><\/figure>\n\n\n\n

Climate Crisis Central apparently triggered Antarctica for this week\u2019s media alarm blitz.<\/p>\n\n\n\n

Antarctic Ice Shelves Suffer Staggering Losses<\/strong><\/em> | Weather.com<\/p>\n\n\n\n

\u2018Shrinking with no sign of recovery\u2019: Scientists issue warning on Antarctic ice shelves<\/strong><\/em>
YAHOO!News<\/p>\n\n\n\n

Scientists count huge melts in many protective Antarctic ice shelves. Trillions of tons of ice lost.<\/strong><\/em>
Associated Press<\/p>\n\n\n\n

Antarctica\u2019s Shrinking Sea Ice Hits a Record Low, Alarming Scientists<\/strong> Bloomberg<\/p>\n\n\n\n

Melting Antarctic Ice Shelves Have Dumped More Than 7 Trillion Metric Tons of Water Into the Ocean  <\/strong><\/em>The Messenger<\/p>\n\n\n\n

Etc., Etc. Etc.<\/strong><\/p>\n\n\n\n

Looks like it\u2019s time yet again to play Climate Whack-A-Mole.  That means stepping back to get some perspective on the reports and the interpretations applied by those invested in alarmism.<\/p>\n\n\n\n

Antarctic Basics<\/strong><\/h5>\n\n\n\n

The Antarctic Ice Sheet extends almost 14 million square kilometers (5.4 million square miles), roughly the area of the contiguous United States and Mexico combined. The Antarctic Ice Sheet contains 30 million cubic kilometers (7.2 million cubic miles) of ice. (Source: NSIDC:\u00a0Quick Facts Ice Sheets<\/a>)<\/strong><\/p>\n\n\n\n

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Highly active volcano Mt. Erebus, Ross Island, Antarctica<\/figcaption><\/figure>\n\n\n\n

The Antarctic Ice Sheet covers an area larger than the U.S. and Mexico combined. This photo shows Mt. Erebus rising above the ice-covered continent. Credit: Ted Scambos & Rob Bauer, NSIDC<\/em><\/p>\n\n\n\n

The study of ice sheet mass balance underwent two major advances, one during the early 1990s, and again early in the 2000s. At the beginning of the 1990s, scientists were unsure of the sign (positive or negative) of the mass balance of Greenland or Antarctica, and knew only that it could not be changing rapidly relative to the size of the ice sheet.<\/p>\n\n\n\n

Advances in glacier ice flow mapping using repeat satellite images, and later using interferometric synthetic aperture radar SAR methods, facilitated the mass budget approach, although this still requires an estimate of snow input and a cross-section of the glacier as it flows out from the continent and becomes floating ice. Satellite radar altimetry mapping and change detection, developed in the early to mid-1990s allowed the research community to finally extract reliable quantitative information regarding the overall growth or reduction of the volume of the ice sheets.<\/p>\n\n\n\n

By 2002, publications were able to report that both large ice sheets were losing mass (Rignot and Thomas 2002). Then in 2003 the launch of two new satellites, ICESat and GRACE, led to vast improvements in one of the methods for mass balance determination, volume change, and introduced the ability to conduct gravimetric measurements of ice sheet mass over time. The gravimetric method helped to resolve remaining questions about how and where the ice sheets were losing mass. With this third method, and with continued evolution of mass budget and geodetic methods it was shown that the ice sheets were in fact losing mass at an accelerating rate by the end of the 2000s (Veliconga 2009, Rignot et al. 2011b).<\/p>\n\n\n\n

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Fig. 1. Antarctic Ice Sheet Regions and Drainage Systems (DS). East Antarctica (EA) is divided into EA1 (DS2 to DS11) and EA2 (DS12 to DS17). The Antarctic Peninsula (AP) includes DS24 \u2013 27. West Antarctica (WA) is divided into WA1 (Pine Island Glacier DS22, Thwaites and Smith Glaciers DS21, and the coastal DS20) and WA2 (inland DS1, DS18, and DS19 and coastal DS23). Includes grounded ice within ice shelves and contiguous islands.<\/figcaption><\/figure>\n\n\n\n

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Contradictory Findings<\/strong><\/h5>\n\n\n\n

A 2021 paper by H. J. Zwally describes the waxing and waning of the Antarctic ice sheet NASA Study: Excess of Mass Gains of the Antarctic Ice Sheet over Mass Losses during 1992 to 2008<\/a> Eliminated by Increasing Dynamic Losses to 2016.  <\/strong>Excerpts in italics with my bolds.<\/p>\n\n\n\n

A new NASA study [Antarctic Mass Balance]<\/strong>\u00a0confirms that an increase in Antarctic\u00a0snow accumulation<\/strong>\u00a0[Siegert, 2003]\u00a0that began 10,000 years ago in East Antarctica<\/strong>\u00a0(EA) [Fig. 1] was\u00a0adding enough ice<\/strong>\u00a0to the continent\u00a0during 1992 to 2008 to outweigh increased losses<\/strong>\u00a0from<\/strong>\u00a0its increasing\u00a0glacier discharge<\/strong>\u00a0into the ocean\u00a0from West Antarctica<\/strong>\u00a0(WA) as previously reported [2015 JOG paper]. Since most other studies reported that the Antarctic ice sheet was losing mass, those 2015 results on gaining mass were controversial. The new study derives\u00a0consistent rates of mass changes over 24 years (1992 to 2016)<\/strong>\u00a0using radar-altimetry data from ESA\u2019s Envisat (2003-10) and gravimetry data from NASA\u2019s GRACE (2003-16), in addition to the prior use of radar-altimetry data from ERS1\/2 (1992-2001) of the European Space Agency (ESA) and laser-altimetry from NASA\u2019s ICESat (2003-08).<\/p>\n\n\n\n

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However, the new study shows that beginning in 2009, the dynamic losses from the outlet glaciers in the WA1 part of WA strongly increased by 119 Gt a-1 (from 95 to 214 Gt a-1), which was further enhanced by an accumulation mass decrease of 39 Gt a-1 in the inland WA2 part of WA. Nevertheless, that\u00a0total decrease of 158 Gt a-1 was not enough<\/strong>\u00a0to bring the whole ice sheet into balance (input equals output),\u00a0because there was a concurrent accumulation mass increase<\/strong>\u00a0of 107 Gt a-1 in EA for three years (2009-11). While that temporary EA accumulation increase diminished, the loss from WA reduced by 71 Gt a-1 and the\u00a0total ice sheet came into balance at -12 \u00b1 46 Gt a-1 during 2012-16, thereby eliminating its effect on sea level rise.<\/strong><\/p>\n\n\n\n

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Fig. 2. M(t) mass time series for West Antarctica (WA), East Antarctica (EA), Antarctica Peninsula (AP), and the total Antarctic Ice Sheet (AIS) from ICESat (blue) and GRACE (red) using the derived equalizing corrections (dBcor and GIAcor) for sub-glacial changes in volume and mass of the Earth\u2019s fluid mantle.<\/figcaption><\/figure>\n\n\n\n

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Fig. 3. ICESat map of dM\/dt total rate of mass change for 2003-2008 with adjusted correction for bedrock motion.<\/figcaption><\/figure>\n<\/div>\n\n\n

\u201cWe now have an accurate record of how the mass balance of the Antarctic ice sheet has changed over 24 years and the causes of those changes.\u00a0Short-term changes for 3 to 8 years have been caused by fluctuations in snowfall and accumulation, but there is no significant trend during 1992 to 2016.<\/strong>\u00a0Mass losses have increased from the dynamic thinning and faster ice discharge of outlet glaciers in West Antarctic, and the large long-term mass gain in East Antarctica has continued\u201d, said lead author Jay Zwally. \u201cHowever, our findings and those of others [e.g. Barletta and others, 2018] also include some\u00a0good signs about the future stability of the West Antarctic ice sheet<\/strong>, about which there has been much concern and predictions of increasing mass loss\u201d.<\/p>\n\n\n\n

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NASA aerial images record West Antarctica melting ice (2016)<\/figcaption><\/figure>\n\n\n\n

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Keeping Things in Perspective<\/strong><\/h5>\n\n\n
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Source: NASA<\/figcaption><\/figure>\n<\/div>\n\n\n

Such reports often include scary graphs like this one and the reader is usually provided no frame of reference or context to interpret the image. First, the chart is showing cumulative loss of mass arising from an average rate of 100 Gt lost per year since 2002. Many years had gains, including 2002, and the cumulative loss went below zero only in 2006.  Also, various methods of measuring and analyzing give different results, as indicated by the earlier section.<\/p>\n\n\n\n

Most important is understanding the fluxes in proportion to the Antarctic Ice Sheet.  Let\u2019s do the math.  Above it was stated Antarctica contains ~30 million cubic kilometers of ice volume.  One km3 of water is 1 billion cubic meters and weighs 1 billion tonnes, or 1 gigatonne.  So Antarctica has about 30,000,000 gigatonnes of ice.  Since ice is slightly less dense than water, the total should be adjusted by 0.92 for an estimate of 27.6 M Gts of ice comprising the Antarctic Ice Sheet.<\/p>\n\n\n\n

So in the recent decade, an average year went from 27,600,100 Gt to 27,600,000, according to one analysis.  Other studies range from losing 200 Gt\/yr to gaining 100 Gt\/yr.<\/p>\n\n\n\n

Even if Antarctica lost 200 Gt\/yr. for the next 1000 years,
it would only approach 1% of the ice sheet.<\/mark><\/em><\/strong><\/p>\n\n\n\n

If like Al Gore you are concerned about sea level rise,<\/strong> that calculation starts with the ocean area estimated to be 3.618 x 10^8 km2 (361,800,000 km2). To raise that area 1 mm requires 3.618\u00d710^2 km3 or 361.8 km3 water (1 km3 water=1 Gt.) So 200 Gt.\/yr is about 0.55mm\/yr or 6 mm a decade, or 6 cm\/century.<\/strong><\/p>\n\n\n\n

By all means let\u2019s pay attention to things changing in our world, but let\u2019s also notice the scale of the reality and not make mountains out of molehills.<\/p>\n\n\n\n

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Let\u2019s also respect the scientists who study glaciers and their subtle movements over time (\u201cglacial pace\u201d).\u00a0 Below is an amazing video showing the challenges and the beauty of working on Greenland Glacier.<\/span><\/p>\n\n\n\n

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